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ASF GitHub Bot logged work on BEAM-4018: ---------------------------------------- Author: ASF GitHub Bot Created on: 24/Apr/18 18:30 Start Date: 24/Apr/18 18:30 Worklog Time Spent: 10m Work Description: jkff commented on a change in pull request #5175: [BEAM-4018] Add a ByteKeyRangeTracker based on RestrictionTracker for SDF URL: https://github.com/apache/beam/pull/5175#discussion_r183836210 ########## File path: sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/splittabledofn/ByteKeyRangeTracker.java ########## @@ -0,0 +1,159 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.beam.sdk.transforms.splittabledofn; + +import static com.google.common.base.Preconditions.checkArgument; +import static com.google.common.base.Preconditions.checkNotNull; +import static com.google.common.base.Preconditions.checkState; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.MoreObjects; +import java.util.Arrays; +import javax.annotation.Nullable; +import org.apache.beam.sdk.io.range.ByteKey; +import org.apache.beam.sdk.io.range.ByteKeyRange; +import org.apache.beam.sdk.transforms.DoFn; + +/** + * A {@link RestrictionTracker} for claiming {@link ByteKey}s in a {@link ByteKeyRange} in a + * monotonically increasing fashion. The range is a semi-open bounded interval [startKey, endKey) + * where the limits are both represented by ByteKey.EMPTY. + */ +public class ByteKeyRangeTracker extends RestrictionTracker<ByteKeyRange, ByteKey> { + private ByteKeyRange range; + @Nullable private ByteKey lastClaimedKey = null; + @Nullable private ByteKey lastAttemptedKey = null; + + private ByteKeyRangeTracker(ByteKeyRange range) { + this.range = checkNotNull(range); + } + + public static ByteKeyRangeTracker of(ByteKeyRange range) { + return new ByteKeyRangeTracker(ByteKeyRange.of(range.getStartKey(), range.getEndKey())); + } + + @Override + public synchronized ByteKeyRange currentRestriction() { + return range; + } + + @Override + public synchronized ByteKeyRange checkpoint() { + checkState(lastClaimedKey != null, "Can't checkpoint before any key was successfully claimed"); + ByteKeyRange res = ByteKeyRange.of(next(lastClaimedKey), range.getEndKey()); + this.range = ByteKeyRange.of(range.getStartKey(), next(lastClaimedKey)); + return res; + } + + /** + * Attempts to claim the given key. + * + * <p>Must be larger than the last successfully claimed key. + * + * @return {@code true} if the key was successfully claimed, {@code false} if it is outside the + * current {@link ByteKeyRange} of this tracker (in that case this operation is a no-op). + */ + @Override + protected synchronized boolean tryClaimImpl(ByteKey key) { + checkArgument( + lastAttemptedKey == null || key.compareTo(lastAttemptedKey) > 0, + "Trying to claim key %s while last attempted was %s", + key, + lastAttemptedKey); + checkArgument( + key.compareTo(range.getStartKey()) > -1, + "Trying to claim key %s before start of the range %s", + key, + range); + lastAttemptedKey = key; + // No respective checkArgument for i < range.to() - it's ok to try claiming keys beyond + if (!range.getEndKey().isEmpty() && key.compareTo(range.getEndKey()) > -1) { + return false; + } + lastClaimedKey = key; + return true; + } + + /** + * Marks that there are no more keys to be claimed in the range. + * + * <p>E.g., a {@link DoFn} reading a file and claiming the key of each record in the file might + * call this if it hits EOF - even though the last attempted claim was before the end of the + * range, there are no more keys to claim. + */ + public synchronized void markDone() { + lastAttemptedKey = range.getEndKey(); + } + + @Override + public synchronized void checkDone() throws IllegalStateException { + checkState( + next(lastAttemptedKey).compareTo(range.getEndKey()) > -1, + "Last attempted key was %s in range %s, claiming work in [%s, %s) was not attempted", + lastAttemptedKey, + range, + next(lastAttemptedKey), + range.getEndKey()); + } + + @Override + public String toString() { + return MoreObjects.toStringHelper(this) + .add("range", range) + .add("lastClaimedKey", lastClaimedKey) + .add("lastAttemptedKey", lastAttemptedKey) + .toString(); + } + + // Utility methods + /** + * Calculates the next {@link ByteKey} for a given key by incrementing by one using byte + * arithmetic. If the input key is empty it assumes it is a lower bound and returns the 00 byte + * array. + */ + @VisibleForTesting + static ByteKey next(ByteKey key) { + return key.isEmpty() + ? ByteKey.of(0) + : ByteKey.copyFrom(unsignedCopyAndIncrement(key.getBytes())); + } + + // Following methods cloned from org.apache.hadoop.hbase.util.Bytes + /** + * @return The value of the input incremented by one using byte arithmetic. It treats the input + * byte[] as an unsigned series of bytes, most significant bits first. + */ + private static byte[] unsignedCopyAndIncrement(byte[] input) { + byte[] copy = Arrays.copyOf(input, input.length); + if (copy == null) { + throw new IllegalArgumentException("cannot increment null array"); + } else { + for (int i = copy.length - 1; i >= 0; --i) { + if (copy[i] != -1) { Review comment: My worry here was that due to a widening conversion from byte to int we might end up with a comparison of 0xff against 0xffffffff which would fail. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org Issue Time Tracking ------------------- Worklog Id: (was: 94738) Time Spent: 7h 20m (was: 7h 10m) > Add a ByteKeyRangeTracker based on RestrictionTracker for SDF > ------------------------------------------------------------- > > Key: BEAM-4018 > URL: https://issues.apache.org/jira/browse/BEAM-4018 > Project: Beam > Issue Type: New Feature > Components: sdk-java-core > Reporter: Ismaël Mejía > Assignee: Ismaël Mejía > Priority: Minor > Fix For: 2.5.0 > > Time Spent: 7h 20m > Remaining Estimate: 0h > > We can have a RestrictionTracker for ByteKey ranges as part of the core sdk > so it can be reused by future SDF based IOs like Bigtable, HBase among others. -- This message was sent by Atlassian JIRA (v7.6.3#76005)